Estimated flow noise levels due to a thin line digital towed array

Flow noise levels for a digital thin line towed array for normal operating speeds of an AUV were estimated using empirical models and towing experiments. The wave number filtering associated with the finite size and distribution of hydrophones in acoustic element of DTLA was applied to the empirical models of turbulent wall pressure spectra to estimate the expected flow noise levels. The empirical results were then compared with the noise spectra measured during towing experiments conducted in a quiet lake. The results showed rapid loss of flow noise energy with increase in frequency arising due to the very nature of turbulent noise spectra and flow noise averaging introduced by the finite size of the hydrophone.